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<p><b>pH</b> is used to describe the acidity of aqueous solutions.<br>
It is defined as:
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		<td>pH = <nobr>&#8722;log{H<sup>+</sup>}</nobr></td>
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where <nobr>{H<sup>+</sup>}</nobr> is the <a href="SP_Activity.htm">activity</a>
of aqueous hydrogen ions.</p>

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